This book constitutes the thoroughly refereed post-workshop proceedings of the First International Workshop on Multi-Agent Systems and Agent-Based Simulation, MABS'98, held in Paris, France in July 1998 in conjunction with Agent World 1998. The 15 revised full papers presented together with an introduction by the volume editors were selected from a total of more than 50 submissions. Among the topics covered are multi-agent systems, social simulation, agent-based modelling, cognitive emergence, honey-bee colonies, artificial societies, economic aspects, cultural evolution, roles in agent systems, applications in various areas, etc.